“He is definitely a character that comes in and becomes a huge influence to the story,” Katherine teases. “He provides insight into some challenges that we have that he has knowledge beyond our own expertise and helps us to solve a lot of problems.”

Will adds, “I think they’re [fans are] going to love that they don’t know where they are with him, and I think they’re going to love that he is everything to anyone who he wants that to be.”

“When we first meet him, he is this kind of this swashbuckling hero who comes in and saves the day,” Will continues. “He and Izzy have sort of a meeting…he’s a bit of a hero in that situation. She has a bit of trouble and he’s very sort of conscientious, very thoughtful.”

Kat also says that Sebastian is a character who connects will the major players, not just Clary.

“[Sebastian] is able to help her [Clary] through a major roadblock that she’s having. So they end up with a very close connection from the beginning, and he helps Isabelle deal with some things as well.”

And that’s not all — “He helps Alec when it comes to his responsibilities, and he’s kind of able to fit himself into our group very quickly. How that will affect things in the future remains to be seen…”